Mr. Saltwater Tank’s 375 Gallon Reef Tank Build Show

375 gallons makes a large saltwater tank. There’s lots of swimming room for fish, lots of places to put corals and lots of opportunities for the unexpected to happen during the tank build process. Fortunately for me, I got all the issues out of the way before the tank got wet.

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Comments for this article (109)

  • Tom says:

    8 feet wide?


  • Jim C. says:

    Great build, I missed it what was the model of your sump?

  • Matt says:

    DAMN! I love the look of big tanks but just seeing how you can barley reach the back of the tank, how on earth do you get your arm in there so clean the glass of the tank and such??

  • Beth says:

    I’d love to know how you managed to keep that tank outside for 3 days on a trailer without anyone either trying to take it or something happening to it. Bart was guarding it right?

  • Beth…I was worried but living in a cul-de-sac likely helped. Anyone messing with the tank would be in plain sight and right underneath a street lamp.

  • Matt…I have a step stool. Since the stand is 36″ tall I’d have to get a stool to work on the tank anyways so I don’t mind the tank height.

  • Jim C…It’s a My Reef Creations biosump

  • adam says:

    thanks sharing this video. there I one thing I see you are running would like to asks you about.. the wireless adaptor you do you ever have issues with it not saying connected.. how do you update your apex with it? I used to use a wire adaptor like that and never had good luck with it.. changed to a powerline adaptor and now it works awesome.. I can even do updates without removing he brain box. and it responds faster to any changes I made.. you should look into a powerline adaptor and I think you will really like it

  • Erik s says:

    awesome tank just started with saltwater 40b. the books are awesome so much info

  • jrock says:

    Mark, I try to catch as many of your shows as I can but I never hear you mention chillers. With all the pumps and stuff don’t you have a chiller?

  • scott p says:

    what a great, detailed overview of a big tank build. I recently took the plunge and upgraded to a 150g tank from an old 75g mixed reef. The Apex controller has been worth every penny(your recommendation BTW). I will be following every update eagerly. My family now agrees that bigger really is better and so cool. the fish are better too. Nice hood, because that 30 inch depth is like mine, you will get wet. well done

  • jrock…no chiller. Not needed.

  • JoelF says:

    WOW! Soon you will have to move into a warehouse for your next tank! How does your wife like the tank? Mine enjoys ours, but constantly worries about water spills. Nice to see damp monitoring. 1 1/2″ piping, would have figured 2″+ for that size of tank. I didn’t catch what size of pump you use for return. Would love to see detail show on how you did the plumbing. Love the LED setup. Am working on DIY fixtures myself.

  • James says:

    The first 6 minutes were a bit hard to make out, all I heard was a whining noise. Other than that….amazing. Nice tank!

  • Dustin says:

    Hey Mark, love the new build! I saw you were dosing calcium and magnesium. Do you dose alkalinity at all? I thought I heard you say you haven’t began dosing kalkwasser yet so how does your alk stay stabilized as you dose calcium ( assuming you aren’t dosing alk already)?

  • Randy says:

    Hi Mark…. What an inspiration you are. 🙂 I’m putting together a tank as we speak and could not figure out the best way to hang my Radions as well. I got the regular/not PRO. I really like the RexRoth rail system you used and would love to do implement that in my build but cannot for the life of me find where to get the rails. Could you please tell me where you purchased them from. Thanks and keep the tips comin’!

  • Bob says:

    Good show! I’d love to see more detail on your water storage/mixing station. I tried to stop the film to see how it was plumbed but, that not being the emphasis of this show, i was unable to see much. Might be a good topic for a show.

  • Roger says:

    Great tank build video thank you so very much I never miss any of your shows,,,,,,

  • Samuel says:

    nice mark love it keep up the good work

  • Peter says:

    Tank looks awesome Mark, and don’t you find it amazing the stuff you really want and need there’s always problems I’ve being waiting 5 weeks now just for my mp40s to come which I’ve paid, but have had a lot of problems with the useless shop I ordered them from

  • Fredrik says:

    Wow, love your tank Mark!!!

  • fabrizio bortoletto says:

    Hi mark,wich biopellet reactor are you using for the tank?
    To decrease the use of gfo and lower po4 i was thinking on purchasing the dr.tim biopellet on…any tips before i buy it?

  • Lisa Foster says:

    You are one lucky duck.
    I’m working on saving up about $600 or so for a 125g acrylic tank…and that’s the biggest I’ll be able to go. And this stuff’s expensive!! It could take me a good two years or more to complete my system on my current budget unless I get lucky and win something or find a massive craigslist deal XD.

    Sorry I had to leave your talk at MAX so early. I really enjoyed it and I’ve learned a lot from you. 🙂 It was great to get to meet you in person.

  • walid says:

    Mark, You should invest in a calcium reactor, it will make your life much easier

  • Matt says:

    Oh this is so unfair … It’s going to take a LONG time to convince the wife that the six foot upgrade isn’t enough …

    Fantastic tank Mark… Love what you’ve done to make it all come together … Just remind me not to let you order a tank for me or choose any lottery numbers for that matter 😉

    Thanks for the awesome and extra long vid… That was a really nice surprise … 🙂

  • Mark H. says:

    Mark, sweet setup. If you ever need a tank sitter let me know. 🙂

  • Randy…RexRoth is only available from Bosch dealers/suppliers and Bosch has designated only one dealer per region. You can find a dealer in your area off Bosch’s site here

  • paulhr says:

    I looked at the web site for and and did not see the “NFS” water storage cylinder in the closet. Do you have a part number & web site?

  • Arthur says:

    That’s one AWSOME setup! I thaught I was the only one who loved cleaning my tank! My family always asks, don’t you get tired of cleaning that darn tank? Hell no! I love it! Thanks for your TV show, I look forward to more.

  • Josh says:

    Murphys law, “Anything that can go wrong, will go wrong”. It’s amazing a shipper can lose something that size. I have had a similar situation, but it was a truck. The tank looks great Mark, I enjoyed the tour of the hardware you have. I was hoping you were going to show us a sump set-up in your basement but realized you rent and the landlord wouldnt be to keen on the idea!

  • Kelley says:

    “Low flow mp40.” Three words you’ll never hear together in my house! Wicked system!

  • Kelley says:


    Your new system is amazing but it has me concerned that future episodes of Mr Saltwater TV won’t apply so much to me and my 75 gallon system. Have you thought of maintaining an extra, more entry level size tank?

  • Josh…and there is no basement in this house!

  • paulhr..”NFS” is not the thing to be looking for. The 55g drum is part #DVT0055-20 from pro tanks and the 40g drum is item #8532 from I forgot that plasti-mart had a 6 week wait time for the tank so I ordered it from somewhere. Even had a 4 week lead time so order way in advance!

  • Kelley…I can understand your concern and I’ve considered a smaller tank but don’t want to deal with maintaining several tanks. That being said, most things I’ll cover on my show will still apply as you can always downsize them. I.e..setting up multiple powerheads on a 75g is similar to a 375, you’ll just have less of them.

  • Reggie says:

    Congrats on the tank Mark. How manny watts are you using for heat? Also, how are you tackling humidity?

  • Reggie…I have a 800w heater and a 200w heater. Humidity isn’t an issue as most of the time the window is open. In the winter it gets a little steamy in this room so I have a box fan to push the humidity out into the rest of the house.

  • Alfredo says:


    Who built your stand and canopy? Can you share the website or contact.. I loved you canopy and I have been looking for someone to make it!


  • Alfredo…a local woodworker built the canopy and he doesn’t have a website. Dutch Aquarium Systems, the maker of the tank, made the steel stand.

  • Buddy says:

    Mark: As always I look forward to every Tuesday and Friday just to see what your doing next or to get a little advise. When I ordered my tank and stand everything went flawless. However I order a lot of things online for delivery and even the best companies manage to mess up now and then. All though your tank is a big bad boy and I would love to have something that big there just isn’t room in my house for something that big. So I’m really waiting to see what you do when you finally buy your own house. Cause it really impacts more of the decision on what size and style of tank you choose. In my case the tank was something I wanted to show case in my home and be able to see all day not just sitting in a spare room off the side. It also had to look like it belonged in the room like a piece of fine furniture. I did find a company that provided me with all those options and it was worth it. It’s not just my tank, it’s my pride and joy too.


  • Randy says:

    Mark… Found a distributor for the aluminum rail. I’m so jazzed. One more question. The screws that mounted the lights that slid into the channel. Did they come with the lights or did you have to buy them? (I don’t have mine yet to check) If you did have to buy them separately, is there anything you can tell me about them. i.e.thread/head size? Thanks again!

  • Drew Stevens says:

    Hi Mark,
    I would like to discuss a 300gal or bigger inwall tank.
    Would you please contact me at your convenience.

  • Randy says:

    Oh and where you got them. The screws are THE key part and I’m just hoping I can find them.

  • Randy…I honestly just walked into my local True Value hardware store and started trying different screws out till I found one that screwed into the Radion and into the Bosch rails. I know they were metric, I just don’t remember what size they are.

  • Adam Abrahamsen says:

    Hey Mark,

    Tank is looking great! Keep up the good work. I know you say you don’t worry about keeping your PH at 8.3 but how are you keeping your PH stable at all without dosing anything?

  • Adam…my pH rises about .15 a day and I’m not doing anything to control it as I’m not worried about the current rise/fall

  • Mike says:

    Hi Mark,

    Is the NetGear box on your electronics board a wireless extension of your wireless router or do you have a direct plug into your router?



  • Mike…it’s a gaming adapter so that I can get the Apex on my network as my tank isn’t anywhere close to my wireless router.

  • Sam says:

    Do you dose Alk at all? you say you add Ca and Mg but not the alk. Was this just a slight slip or true?

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